Currently, jet devices commonly used in solar water heaters are adapted for high-pressure systems, the pressure of which is provided via two methods.
One is to place the water heater on the roof for taking advantage of gravity drop to provide with pressure for hot water. However, once the gravity drop falls, it may cause problems such as less outflow of hot water because of the insufficiency of pressure provided. Hence, when people are taking a shower, they may feel uncomfortable because of the low temperature of water. Additionally, it may cause counter flow due to a considerable pressure discrepancy between hot water and cold water.
The other method is to dispose a pressure supplier in the water heater for providing pressure for hot water. Although it may solve some problems like insufficiency of pressure of hot water, the pressure supplier is added and the water heater is required for bearing pressure accordingly, which may greatly increase the cost and go against quantity production.
To solve the above described problems of prior art, China patent literature with publication No. CN102767210A discloses an adjustable jet device with multiple water sources, comprising a jet device body, a fluid chamber, a needle, a throat pipe, a diffuser, an inlet of the jet device (a cold water port), an inlet for sucked fluid (a hot water port), wherein the fluid chamber is disposed inside the jet device body, a nozzle is disposed at the front end of the fluid chamber, and the needle is disposed along the extension center line of the nozzle within the fluid chamber. Cold water with high pressure flows into the jet device through the inlet of the jet device and passes the fluid chamber till the nozzle. Then cold water is injected with high speed into the throat pipe along the needle, and negative pressure is formed in the throat pipe by entrainment effect, which may pump the hot water from the hot water port interconnected with the throat pipe. Based on the principle of entrainment effect of high speed jet, the invention of prior art may solve the problem of insufficiency of pressure for hot water supplied by non-confined water heater, and the energy of pumped fluid may be increased by high speed jet and the overall pressure of the device of the invention may be enhanced. However, it may still have some problems when using it.
In the present technology, the distance between the nozzle and the throat pipe is fixed, so as to form an opening, through which hot water flows into the throat pipe. No matter under what circumstances, water flowing out of the throat pipe always contains a certain proportion of hot water. Given this circumstance, the temperature of water flowing out of the throat pipe may not equal to the temperature of cold water, so that it may be too hot for people to take a shower and impossible to decrease, especially in summer.
Thus China patent literature with publication No. CN102086941B discloses a mixing valve comprising a valve body, a hot water port, an outlet. The mixing valve further comprises a nozzle in connection with a cold water port of the valve body; a cold water inlet and a cold water outlet are disposed on the nozzle; a chamber for adjusting water temperature is disposed in the valve body and is in connection with the hot water port; and a chamber for mixing water is disposed in connection with the outlet. The chamber for mixing water and the chamber for adjusting water temperature are in connection with each other through the outlet for hot water disposed at one end of the of the chamber for adjusting water temperature, and the chamber for mixing water is also in connection with the nozzle cold water outlet through the cold water outlet. For adjusting the flow of hot water, people only need to screw on or screw off the nozzle of the valve body for increase or decrease the cross section of the outlet for hot water, for adjusting the flow of cold water, people only need to screw on or screw off needle to adjust the cross section of the outlet of nozzle. It solves the problem of the jet device provided in China patent literature with publication No. CN102767210A, i.e. water flowing out of the throat pipe always combined with hot water. Thus people may feel more comfortable for taking a shower in summer. However, it still has some problems during the actual applications, which are:
1. For getting mixed water with comfortable temperature, people need to adjust the nozzle and the needle respectively in order to adjust the hot water inflow and the cold water inflow. However, during the actual application it may be difficult for the users to adjust the two valves simultaneously for adjusting mixed water temperature, and it is prone to be operated by mistake. Even when it is too hot for the user to take a shower and the cold water port is required to be turned up, the user may be scalded if they turn up the hot water port by mistake.2. When the nozzle of prior art is adjusted in the axial direction of the adjustable jet valve, the pressure of cold water of the cold water inlet disposed thereon is kept the same with the pressure of cold water of the cold water port disposed on the valve body. When people screw on or screw off the nozzle, the needle is forced to rotate with the nozzle, meanwhile there is no relative motion between the nozzle and the needle, so as to maintain the cross section of the outlet for cold water. Thus, when the cross section of the cold water port is smaller than that of the outlet for cold water, the pressure of the cold water in the nozzle may be too low to get a good jet effect, or no jet is actuated. Thus for better jet effects, the needle is required to be adjusted as well for decreasing the cross section of the outlet for cold water, which means the needle and the nozzle are required to be adjusted simultaneously which is more difficult for the users. Otherwise water with comfortable temperature may not be surely discharged if people do not adjust the needle and the nozzle together. In the present invention, since the pressure of the cold water of the cold water inlet is kept the same with the pressure of the cold water of the cold water port, the problem mentioned above may not exist.3. There is a problem that exists both in China patent literature with publication No. CN102086941B and China patent literature with publication No. CN 102767210 A, i.e. the needle within jet device is a slender structure with a tip. The cost for such needle is quite low, and when the fluid is passing the nozzle with a lower pressure, the needle with a slender structure bears low pressure in its radial direction, it may satisfy the working requirements. But if the fluid is passing the nozzle with a great or greater pressure and an instable fluid velocity, the needle may bear great and non-uniform radial pressure in its radial direction, i.e. along the length direction of the needle, different portions may bear different pressures, which may cause deviation of the needle from the spout of the nozzle as well as the radially swinging of the needle, and further impact the jet effect of the nozzle.